david muir. They were harsh words, I hope she rots in hell but those are words from a daughter whose mother resurfaced after intentionally disappearing leaving her daughter for more than a decade and made us wonder with parents like these -- people think it's the greatest that boob of motherhood voluntarily leaving your children, daking a time-out that can stretch into years but moms I met are convinced that what they have done has made them better mothers, you decide. Mother of the year she isn't. 11 years ago, brenda heist dropped off her 8 and 12 year old children at school, and then vanished. In news reports, her grieving family said they assumed she'd been kidnapped or murdered. It was tough. I mean every prom -- i graduated. And she wasn't there. Reporter: But last month heist finally reappeared looking worse for wear and made a stunning admission. She had abandoned her family on purpose. It's the rare extreme of a mom gone awol. The reaction? Widespread revulsion. Don't judge, says mom talyaa liere. She's no brenda heist, not even close, but she's faced similar scorn for deciding to live apart from her children. I had a lot of shame because of the way that we think about what mothers should be. Reporter: That they would never leave their children? Some people think that. Reporter: Talyaa is a so called "non custodial mother." A mom without physical custody of her kids. In 2008 she moved to seattle after a divorce, leaving her three children nathaniel, eric and serena to live with their dad, david, 2800 miles away in pennsylvania. Talyaa spends her days painting, writing, making music and practicing martial arts with her boyfriend. Mothering -- give me a wide shot of her room hiv want to see who it looks like. Reporter: It's done from afar. I'll walk you through the steps of scrambled eggs. Reporter: Oh sure, she emails recipes for them to cook themselves and she stays in touch on the phone and via skype. You sound a little like you have a cold. Yeah, I have a cold. Reporter: But they only see each other in person around once a year. Okay so, miss sweetcake, I'll talk to you again soon. We talk all the time. We're very connected. Reporter: And that's as good as being there? I can't answer that it's, it's good as. It's just different. Reporter: I know a lot of people listening to this will want to know, do you love your children? Absolutely. More than anything. Reporter: More than yourself? Should a mother love her children more than herself? Reporter: Startling as this may sound, there are an estimated 2.4 million non-custodial mothers in the united states. Many of these mothers are heartbroken by the loss of custody. But some moms, like talyaa, give up custody voluntarily. Author rahna reiko is also a non-custodial mother. Her teenage sons were three and five when she and her husband divorced. Since then, she sees them for four to five hours, three days a week, an arrangement she initiated. They come over after school, they stay until bedtime, and then he comes to pick them up, and they go home to bed. Reporter: Rahna is brutally honest about why she made her decision. I never wanted to be a mother initially. I realized that I had -- that i had kind of fallen into this role that I had never intended to fall into. Reporter: Rahna wanted to devote herself full time to her writing, not to her kids. She's the rare mom to admit she does not pine for the daily grind of parenting. I don't have to get them to brush their teeth. I don't have to be up until 11:30 to do their homework. I don't miss that. Reporter: Talyaa has a different reason for leaving. She says post divorce conflict between her and david was causing enormous stress for her and the kids. And that leaving, while a wrenching decision, was the only way to ease the tension. Why so far away? Why did you have to get, move 3,0000 miles away? Well, at that point, was it ten miles or three thousand miles or three million miles. It really wouldn't make any difference. Reporter: Well, because at the kids and have, be a presence in their lives. Reporter: David says there was no conflict and he says talyaa's sudden transformation from stay at home mom to west coast bohemian was astonishing. I'm completely surprised, even to this day. Reporter: And his friends? They were shocked. It's like, how could a mom leave her children like this? What got into her? Hi, momma. But she has a spiritual connection with them that is rather profound. And accordingly, she doesn't seem to need to have that physical contact with them. How's my boy? Reporter: Complicating matters further, taylaa's youngest child eric has down syndrome. Their longest time apart was more than two years. Kisses with mom? A computer will have to do. You have a special needs child. Did it make you think that you owed it to him to be there for him? Eric is the kind of child that connects to whomever he's around. It sounds strange to say this from his mother, but people are kind of interchangeable to him. I could tell from how he is that he will have a wonderful life, whoever he's around. Reporter: Talyaa has been called "selfish", "irresponsible" and "delusional." Rahna has been called worse. I got death threats. I got people telling me i am evil, that I'm worse than hitler, that I'm, that I'm human garbage. Reporter: Some mothers would say your decision to leave was putting care for yourself ahead of care for your children. I think that better women make better mothers. When you love and know yourself, then you can be a better mother for your children. Reporter: But how are you being a better mother 3,000 miles away? Because I'm in touch with who I am. I know, but how is that benefiting them? It allows me to make choices for my children from my heart rather than from what I think society tells me about what a mother should be. I never saw him play his drums. You haven't? I don't think I have. Reporter: You chose to be a mother. Responsibility and saying, well, i, I don't wanna sacrifice anything? Shouldn't mothers sacrifice for their children? I think no mother should have to completely sacrifice. I think to sacrifice your own wants and needs and desires for someone else's life, what kind of a message is that sending your children? Reporter: Here's a surprise. Not only his her ex-husband satisfied. I think it's great. Reporter: Her son supports his mom despite the distance. Yeah, it's difficult, but, no, I'm not going to grow up hating her and never speaking to her again. I think my mom's a good mom, even from far away. Reporter: But for 11-year-old serena, who was only 8 when her mom left, the emotional toll is palpable. I was growing up, and my mom lived with us, then, um, i have, like, a lot of happy memories. Reporter: Serena saves every memento from her mother. These are some christmas WRAPPINGs I SAVED. Are my birthday cards. They are kind of special because we don't see her a lot.. Reporter: She has also become a surrogate mother for eric. I make eric's lunch and i feed him breakfast. Sometimes I am actually kind of angry with her. That I don't have a mother to do what a mother does. Reporter: In her blog "the better mother's project" talyaa defends her decision with her message that there is not only one "right" way to be a mother. Rahna agrees. She says she has managed to have it all, an award winning book and a close relationship with her sons.. I think if I was a man none of this would be an issue. People have this idea of what a good mother is, um, that somehow their, I don't fit that mold. But I definitely fit the mold of a terrific divorced dad. Reporter: Talyaa has lived apart from her children for 5 years now. We checked in with serena just last week. She is 13 years old now and says adjusting to life without mom has become easier. Our relationship is really close now, and, a lot closer than it was before. We can talk about relationship issues and what goes on in a girl's body. He's going to ask her out -- i really love my mom a lot. Reporter: But serena's vision of her future life as a mother? As a mother, I never wanna be apart from my children. I want to make that perfect family that she was never able to do. I want that really badly now. Mamma loves you. Bye. So, what do you think about these mothers who move out? Let us know on twitter usi using #abc2020. We'll be right back.

This transcript has been automatically generated and may not be 100% accurate.

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